#include <stdio.h>#include <iostream>#include <string.h>#include <string>#include <limits.h>#include <algorithm>#include <math.h>#include <numeric>#include <functional>#include <ctype.h>#include <vector>#define MAX 60#define MAX_DIGIT 200using namespace std;vector<int> vec_array[MAX];int n,m;int multiply(int* a,int ca,int* b,int cb,int* c) { int i,j,* s; s=(int*)malloc(sizeof(int)*(ca+cb)); for (i=0;i<ca+cb;i++) s[i]=0; for (i=0;i<ca;i++) for (j=0;j<cb;j++) s[i+j+1]+=(a[i])*(b[j]); for (i=ca+cb-1;i>=0;i--) if (s[i]>=10) { s[i-1]+=s[i]/10; s[i]%=10; } i=0; while (s[i]==0) i++; for (j=0;i<ca+cb;i++,j++) c[j]=s[i]; free(s); return j;} bool in_degree[MAX],visit[MAX];void dfs(const int &x){visit[x]=true;for(int i=0;i<vec_array[x].size();++i)if(!visit[vec_array[x][i]]){in_degree[vec_array[x][i]]=true;dfs(vec_array[x][i]);}}int main(void){ int u,v; while(~scanf("%d%d",&n,&m) && n+m) {for(int i=1;i<=n;++i)vec_array[i].clear();for(int i=1;i<n;++i){scanf("%d%d",&u,&v);vec_array[u].push_back(v);vec_array[v].push_back(u);}memset(visit,false,sizeof(visit));memset(in_degree,false,sizeof(in_degree));for(int i=1;i<=n;++i)if(!visit[i])dfs(i);int a[MAX_DIGIT],b[MAX_DIGIT],c[MAX_DIGIT];int ca=0,cb=0,cc=0;int tmp=m;if(in_degree[1])--tmp;if(tmp>9){a[0]=tmp/10;a[1]=tmp%10;ca=2;}else{a[0]=tmp;ca=1;}memset(b,0,sizeof(b));memset(c,0,sizeof(c));for(int i=2;i<=n;++i){tmp=m;if(in_degree[i])--tmp;if(tmp>9){b[0]=tmp/10;b[1]=tmp%10;cb=2;}else{b[0]=tmp;cb=1;}cc=multiply(a,ca,b,cb,c);memcpy(a,c,sizeof(a));ca=cc;} if(ca==0) printf("0"); else for(int i=0;i<ca;++i) printf("%d",a[i]);printf("n"); } return 0;}
